Are you one of those travelers who travels the world for two weeks and bring no more than a carry-on bag or backpack?

If you answered "yes", I have a new discount travel option that will work for you: international air courier. Crossing international datelines, secrets stashed in a leather briefcase, handcuffed to your wrist -- It sounds romantic and risky, but it is not like that at all.

It can, however, save you some big bucks.

Recently I meet up with David Knapp at San Francisco International Airport. He was flying to China, but was first connecting with a representative from AirMule, a web-based courier company.

The AirMule representative handed David a fully packed suitcase, which he unzipped and looked through. Nothing out of the ordinary -- just shoes, clothing and other unremarkable items.

For taking the bag to China, David gets $150. If he takes two bags, $300. If he takes them there and back he gets $600 -- about half the cost of a round trip ticket to China.

"It's basically like just having a piece of luggage," David says. "You go through customs just like everyone else."

Once customs is cleared, David meets up with another AirMule representative in China and hands off the bag.

Rory Felton, AirMule co-founder and president, says by putting that luggage capacity to work, air travel gets cheaper. "A lot of young people just carry on, so they get two checked bags allowed on their ticket that are going unused."

Felton says there's money to be made with all the back and forth between San Francisco and China, even if couriers didn't by their own tickets.

"They might be travelling to China for work, they might not even be paying for their ticket, their company might be, and so any money they can make from their unused checked luggage space is just money in their pocket," he says.

So, it's profitable, but is it safe?

David says he's never had a problem, and AirMule's president says the courier and shippers are TSA checked, so there are no issues.

Sean Yang, AirMule's CEO and co-founder, says he does not shy away from comparisons to rideshare company, Uber.

"You could say it that way," he says. "We are like the Uber for FedEx or UPS."

AirMule claims to be cheaper, faster and more secure for small e-commerce shippers, like many of those selling on eBay.

That brings us back to courier David Knapp and that secret handcuffed briefcase. He says when he first heard of AirMule he thought of clandestine meetings and kind of liked the idea. "The 80's view of the courier," he says. "It's funny because when that was around, I wanted to do that then, too."

Travelers interested in being an international courier can sign up at Airmule.com, where they can share when and where they are flying and how many suitcases they can take. If there is a need, the company gets in touch.

Right now the flights are from LAX and SFO but as AirMule expands, so will airports here and abroad.

Have you contacted the company but your complaint still isn't resolved? Have you asked to speak with a supervisor? Have you read the 7 On Your Side FAQs? If you live in the San Francisco Bay Area and you're still having trouble, 7 On Your Side wants to help you.